JPS6038587B2 - automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control system for an automatic transmission equipped with a direct clutch for automobiles, particularly passenger cars.

Automatic transmissions for passenger cars, which combine a torque converter with a planetary gear unit and use a hydraulic control device to change gears to best suit the driving conditions, are easy to shift and offer excellent ride comfort, so they have become quite popular. It's coming to an end.

However, torque converters have the disadvantage of increased fuel consumption due to the energy losses inherent in them, a problem that needs to be solved in today's era of emphasis on fuel economy. Nowadays, with the development of expressways, it is now possible to drive for long periods of time with little change in running resistance. A direct coupling clutch is installed between them, and when the rotation ratio of the driving and driven barrels reaches a speed ratio higher than the clutch point, the direct coupling clutch is activated by hydraulic control, preventing energy loss due to the torque converter during direct coupling operation, and reducing power. The conduction efficiency can be increased to nearly 100%, and fuel consumption can be reduced accordingly.

On the other hand, if the torque converter is filled with oil during direct-coupling operation, the guide vanes are stationary, which induces an invalid flow in the circuit, resulting in energy loss, which contradicts the above. arise. It would be possible to empty the oil in the torque converter each time a direct connection is made, but this would complicate the mechanism and operation, so many models have a structure in which the pump and turbine are integrated, that is, the guide vanes rotate idly when directly connected. This invention detects when the speed difference between the driving shaft and the driven shaft of the torque converter becomes a drop or near zero in a hydraulic control system for an automatic transmission in which the torque converter is combined with a planetary gear device equipped with a direct coupling clutch. A comparator is provided in the control circuit, and the signal causes the hydraulic circuit to engage and release clutches, brake bands, etc.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a block diagram illustrating the control system of the control device according to the present invention, and FIG. 2 is an explanatory diagram of the main parts of the hydraulic circuit of this pedestal. 1 is the front clutch, which connects the intermittent date sun gear to the torque converter, 2 is the rear clutch, which connects the second sun gear to the torque converter, and 3 and 4 are the brake bands, which connect the second gear and the planetary clutch. It is a carrier brake.

These operations are performed by a hydraulic piston and a return spring, and the hydraulic pistons provided in each will be identified by the same numbers and will be described below.

The front clutch 1 is made to operate when the forward high speed gear is set and the reverse gear is set, the rear clutch 2 is made to be operated when the forward gear is set, and the brake bands 3 and 4 are made to operate when the forward gear is set. 3 is activated, and when the forward high-speed gear is set, the fastening gear 3 is activated first, and then the release side 4 is activated by applying hydraulic pressure to release the brake band.

In addition, a final stage clutch (low and reverse clutch) is not shown, but is operated when the forward low speed gear is set and when the reverse gear is set.

Table 1 shows the working pressurized oils introduced into the hydraulic pistons of the front clutch 1, rear clutch 2, and flake band 3, respectively, as shown in Table 1.

5 in Table 1 is a torque converter, and 6 is its direct coupling clutch.

7 is an oil cooler for the converter 5, and 8 is a pressure holding valve.

A is a spool valve that is moved to the left by a solenoid S, switches the oil path, and is returned to its original position by the elastic force of the coil spring at the left end.

R is a comparator built into the torque converter direct-coupled controller, and it compares the speed difference △n between the driving shaft of the torque converter 1 and the driven koji, and the speed difference limit standard △n, which is set to a constant value.
A solenoid S is operated by an output signal r which is output when a signal corresponding to o is input and the ratio Δn to Δ is reached.

Subur valve B supplies hydraulic oil to front clutch 1■
The pressure-receiving area of the spool and the spring are designed so that the spool moves to the right against the elastic force of the coil spring at the right end only when the hydraulic oil and the hydraulic oil ■ are simultaneously fed to the side where the brake band is fastened. A constant is set. Subur valve C is provided in the exhaust circuit from torque converter 5. D is check valve, E is accumulator,
F is an orifice. Note that the small arrow at the outlet of the oil passage indicates the drain. Next, the operation of this hydraulic control device will be explained.

When the condition of △nS△ ratio is realized from the speed difference △n between the driving shaft and driven shaft of the torque converter 1 and the speed difference limit reference △ratio during driving, the solenoid S is activated by the output signal r from the comparator R. Operate. The spool of the spool valve A is pushed to the left by the operation of the solenoid S, the oil path is switched, and the hydraulic oil (■) for the rear clutch 2 is sent to the spool valve B. On the other hand, as shown in Table 1, in the forward high speed running state, hydraulic oil ■ and hydraulic oil ■ are simultaneously fed into spool valve B, so the coil spring on the right end is compressed and the spool moves to the right. , and each oil stalk is switched. As a result, the hydraulic oil (2) is sent through the spool valve B to the direct coupling clutch 6 of the torque converter 5, the clutch is connected, and both the driving and driven shafts of the torque converter 5 are directly coupled. The hydraulic oil introduced into the direct coupling clutch 6 pressurizes the right end surface of the spool of the spool valve C, moves it to the left against the elastic force of the coil spring, and is discharged from the torque converter 5 through the discharge oil path. will be closed. As a result, the circulation flow of the hydraulic oil in the torque converter 5 is blocked, and energy loss due to the circulation of the hydraulic oil (2) is prevented. When hydraulic oil ■ is sent to the front clutch 1, the check valve D is pushed up and activated immediately.
Torque converter 5 which is directly connected in forward high speed running state
The direct coupling clutch 6 must be released first.

For this purpose, hydraulic oil is used when releasing front clutch 1■
In response to the return, the Oriswiss F in the branch oil path is lowered, and the increase in pressure of the return oil at that time is absorbed by the accumulator E, which delays the return of the hydraulic oil ■ and creates a time lag in the release of the front clutch 1. It will be done. The hydraulic oil ■ introduced to the brake band engagement side 3 during forward mid-range driving causes the spool valve B to return to the right side, and the hydraulic oil ■ to the direct coupling clutch 6 is connected to the drain circuit and the clutch is released. , the brake band 3 is fastened, and the vehicle can begin midway driving. The operation of directly connecting the direct coupling clutch 6 of the torque converter 5 has been described above, but once the accelerator pedal is released after the high speed running gear is set or just before the high speed gear is set, the high speed gear is set. Since the engine rotation decreases in this state, a timing is obtained when the speeds of both the driving shaft and the driven shaft of the torque converter 5 match.

At this time, Δn is 0, and the direct coupling clutch 6 is connected without any impact. When the engine load increases with the torque converter being directly connected, or during kickdown, the Subur valve B is returned to the left by the hydraulic oil ■, and the hydraulic oil for the direct coupling clutch 6 is discharged to the drain, and the torque converter 5 The direct connection of is released.

Thereafter, the front clutch 1 is released and a medium speed or low speed gear is set via the torque converter 5.

As is clear from the above explanation, the automatic transmission according to the present invention directly connects the driving shaft and the driving shaft of the torque converter through the direct coupling clutch, and the direct coupling operation can be performed smoothly and reliably when driving at high speed. On the other hand, the direct coupling clutch is automatically released when the engine load increases in the direct coupling state or in the event of a kickdown, reducing the increase in fuel consumption in automatic transmissions using torque converters. The situation can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the control method of the control device according to the present invention, and FIG. 2 is an explanatory diagram of the main parts of the hydraulic circuit of this device. 1: Front clutch, 2: Rear clutch, 3: Brake band (engagement side), 4: Brake band (release side),
5: Torque converter, 6: Direct clutch, A, B, C
: Spool valve 1st, 2nd, 3rd, D: Check valve, E: Accumulator, F: Orifice, R: Comparator, S: Solenoid. Pseudo-1 Figure 2

Claims (1)

[Claims] 1 In a transmission device that combines a torque converter with a direct coupling clutch and a planetary gear device, a detection signal of a speed difference between a driving shaft and a driven shaft of the torque converter is received and compared with a predetermined speed difference reference limit value. a first spool valve actuated by the output signal of the comparator, and a first spool valve that supplies the first spool valve to the direct coupling clutch only when hydraulic oil to the front clutch and hydraulic oil to the brake band engagement side are simultaneously introduced. a second spool valve configured to send hydraulic oil to the rear clutch through the first spool valve; and a third spool configured to block the hydraulic oil circuit of the torque converter by supplying hydraulic oil to the direct coupling clutch. An automatic transmission device comprising a valve and a hydraulic circuit designed to provide resistance to hydraulic fluid returning from a front clutch.